[cluttermm_tutorial] Use C++11

[Murray Cumming <murrayc src gnome org>]

commit e880b76de64c47e71c8f145216fa368f56c5faad
Author: Ian Martin <martin_id vodafone co nz>
Date:   Wed Feb 24 14:55:16 2016 +0100

    Use C++11
    
    See bug #761971

 configure.ac |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 8954fda..fc23049 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,7 +26,9 @@ AC_CONFIG_HEADERS([config.h])
 AM_INIT_AUTOMAKE([1.8 -Wall gnu no-define nostdinc])
 AC_ARG_VAR([ACLOCAL_FLAGS], [aclocal flags, e.g. -I <macro dir>])
 
-AC_PROG_CXX()
+AC_PROG_CXX
+AX_CXX_COMPILE_STDCXX_11()
+
 PKG_CHECK_MODULES([TUTORIAL_MODULES], [cluttermm-1.0 >= 1.3.1 clutter-gtkmm-1.0 >= 0.9.6])
 
 AC_LANG([C++])